Final answer:
According to Lon Fuller, law must be certain, clear, and known to the public in order to be effective. It should provide guidance and stability and should not be ambiguous, arbitrary, or retroactive. Fuller believed that adherence to these principles would ensure that laws are fair and just.
Step-by-step explanation:
According to legal philosopher Lon Fuller, law must be certain, clear, and known to the public in order to be effective. He argued that laws should not be ambiguous, arbitrary, or retroactive, but instead should provide guidance and stability for individuals and society as a whole.
Fuller believed that adherence to these principles would ensure that laws are fair and just.